The principal chemical constituents of plant bodies such as wood and vegetation are cellulosic materials such as cellulose, hemicellulose and lignin. Of the cellulosic materials, cellulose and hemicellulose are high-molecular weight materials in which saccharides are bound in a straight- or branched-chain shape.
Such cellulosic materials are known to be converted into saccharides by hydrolysis. Such hydrolysis methods include an acid hydrolysis method and an enzymatic hydrolysis method.
However, the efficient hydrolysis of a cellulosic material is not easy.
For example, in hydrolysis using an acid, although a reaction proceeds in an extremely short time on the minute time scale, reaction control is difficult due to the occurrence of heat generation. Even if the reaction control is enabled, constituents in a cellulosic material are prone to be excessively decomposed and carbonized, and therefore a saccharide cannot be obtained in a sufficient yield.
In hydrolysis using an enzyme, although constituents in a cellulosic material are not excessively decomposed, the proceeding of a hydrolysis reaction is slow, sometimes requires 48 hours or longer. There may be also a method using a large amount of an enzyme for increasing the yield of an obtained saccharide and a hydrolysis rate, which method has the disadvantage of increasing the cost.
In contrast, research has been conducted on methods of undoing the entanglement of lignin with cellulose and hemicellulose by carrying out some sort of treatment prior to the enzymatic hydrolysis of cellulosic materials.
For example, a method in which wood is finely pulverized and then the enzymatic hydrolysis of the pulverized wood is performed (for example, see Patent Document 1 or 2); a method in which acid is added to a plant body containing lignocellulose and the mixture is heated by microwaves and subjected to acid hydrolysis (for example, see Patent Document 3); a method in which a cellulose-containing material is treated with a dimethylformamide solution containing nitrogen oxides and thereafter subjected to enzymatic hydrolysis (for example, see Patent Document 4); a method in which a lignocellulose-based biomass is treated with pressurized hot water and subjected to mechanical pulverization and then to enzymatic hydrolysis (for example, see Patent Document 5); and the like are disclosed.    Patent Document 1 Japanese Patent Application Laid-Open Publication No. 55-9758    Patent Document 2 Japanese Patent Application Laid-Open Publication No. 63-137690    Patent Document 3 Japanese Patent Application Laid-Open Publication No. 59-146594    Patent Document 4 Japanese Patent Application Laid-Open Publication No. 61-242591    Patent Document 5 Japanese Unexamined Patent Application Publication No. 2006-136263